Screening for betalactam resistance* using Cefpodoxime 10 µg disk

SRGA breakpoints on ISA (Oxoid), semiconfluent inoculum, 18-20 h incubation, 36 C, ambient air:
For E.coli, Klebsiella pneumoniae and K.oxytoca use ESBL-screen negative >25 mm; and ESBL-screen positive zone diameter <24 mm
For Proteus mirabilis the corresponding values are 30/29 and for Citrobacter spp 20/19 mm.

*Cefpodoxime indiscriminately picks up ESBL-, AmpC- and OXY-enzymes.
Further testing is needed to differentiate between the various enzymes.